This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To 1) develop strategies for creating genetically identical monkeys using blastomere separation and 2) propagate a family of MHC-defined monkeys using assisted reproductive technologies. Genetically identical and MHC-defined monkeys would be extremely valuable models for biomedical studies of human disease. Progress early in the project was hampered by limited numbers of appropriate female rhesus monkeys for assignment. During the last reporting period, however, with a no cost extension of the grant, remarkable progress in the refinement of techniques was accomplished. There have been several successful transfers of split embryos with pregnancies in progress. This research used WNPRC Animal Services. Note: AIDS related